1. Field of the Invention
This invention relates generally to portable abdominal exercise machines and more specifically to abdominal exercise machines providing visible and physical feedback to users when proper abdominal crunch exercises are performed.
2. Description of the Related Art
Abdominal exercise machines, even portable abdominal exercise machines, are well known in the art. U.S. Pat. No. 5,964,685 issued Oct. 12, 1999 to Kevin O'Brien Boland discloses an abdominal and arms muscle exercise device designed to be used on the lap of the individual for conditioning the abdominal and arm muscles. The device is lap supported with a linear pair of sidewall members, an elongate cross-member with terminal upswept handles. A lower elongate cross bar is tucked into the user's lap and the upstanding pair of support members extends to a cross bar which rests against the upper torso of the individual using the device.
U.S. Pat. No. 5,851,167 issued Dec. 22, 1998 to Tianfu Li discloses an exerciser that is used to improve the muscles and may be used in various ways, including a sitting position. The device comprises an elastic ring that extends from an elastic flexible rod along with one spiral ring and two pairs of grips. The device may be used for muscular strengths of the arms by pushing and pulling the grip pairs.
U.S. Pat. No. 6,056,676 issued May 2, 2000 to Cleveophis Adams discloses an exercise device and a method of its use. The device is designed to facilitate the strengthening of abdominal and back muscles and includes a resistance member that is coupled between a lap engageable base and an arm positioning member. The device includes a lap engaging frame with an annular rim member that is adapted to rest on the lap of the user. The tubular central support or cross member extends between and is affixed to opposite sides of the rim member to support a pair of curved thigh brace members. The thigh brace members are adapted to engage and bear forcibly against the inner thighs of user. Resistance member is provided between the lap engaging frame and the hand brace members.
U.S. Pat. No. 5,891,005 issued Apr. 6, 1999 to Henry Drukarov discloses a head and neck support for abdominal exercise. The abdominal exercise device comprises a base member with a cylindrical member secured to the forward edge thereof An upper member is hingedly coupled to the forward edge of base member and receives a handle portion which is adjustably received within the open rearward edge. The handle portion includes a cross-bar.